Little evidence exists in the literature for how to manage clients who self-harm within low, medium and high secure forensic wards, despite the identified high rates of self-harm within these services. This study sought to investigate the management practices used with clients who self-harm in low, medium and high secure forensic wards, how helpful staff consider these practices and what understanding staff have of the reasons for which clients self-harm. A Delphi survey methodology was employed across three rounds using a multidisciplinary cohort of forensic ward staff, across low, medium and high wards. Physical management strategies were reported as most frequently employed to manage self-harm. Relational approaches to managing self-harm showed the highest rate of consensus for their helpfulness in practice. Consensus was reached across numerous domains explaining reasons for self-harm, including as a ‘communication of distressing feelings’. Statements indicating a negative view of self-harm such as ‘to manipulate staff and gain attention’ received consensus of disagreement. Psychological models and approaches used by clinical and forensic psychologists in the cohort were identified, and helpful elements of these models were identified, including ‘positive focus of approach’ and ‘emphasis on relational working’.